This proposal focuses on the neuroendocrine regulation of reproductive processes in the yellow fever mosquito, Aedes aegypti. Three types of neuropeptides have been isolated from female heads: 1.) ovarian ecdysteroidogenic hormone (OEH, also known as EDNH), which stimulates yolk deposition in blood-fed, decapitated females and secretion of ecdysteroids by ovaries in vitro; 2.) hypertrehalosemic/adipokinetic hormone (HT/AKH), which releases total soluble carbohydrates and depletes glycogen stores in isolated abdomens; and 3.) enkephalin-like peptides known, in vertebrates, to stimulate food ingestion and alter behaviors antagonized by Arg-Phe-NH2 type peptides, but as yet of unknown function in mosquitoes. Large-scale extractions of female heads and subsequent HPLC purification will provide sufficient quantities of the peptides for structural characterization. Once the amino acid sequences of the peptides are known, they will be-synthesized for use in studies to define the physiological properties of the peptides. Antisera that specifically recognize each of the synthetic peptides will be produced and applied in immunoassays to quantify the peptide in tissues and hemolymph during oogenesis and to identify the cellular sources. The biological activity of synthetic peptides will be examined by physiological studies of tissue-specific processes, e.g. mobilization of sugars by HT/AKH, and by behavioral studies, e.g. stimulation of nectar ingestion by enkephalins. The goal of this research is to elucidate the regulation of interrelated reproductive processes at three levels: feeding behavior, energy metabolism, and oocyte maturation. once it is possible to genetically transform mosquitoes, neuroendocrine regulation of reproduction will be a promising target for genetic manipulation to prevent mosquito development or block pathogen transmission by mosquitoes.